Page 26 - 《广西植物》2024年第10期
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types of abnormally colored leaves and normally red ̄colored leaves of L. chinense var. rubrumꎻ we also analyzed
differences in bacterial diversityꎬ community structureꎬ and functional levels among differently colored leaves. The
results were as follows: (1) Compared with the normally red ̄colored leavesꎬ we detected higher biomass of endophytic
bacteria in the five types of abnormally colored leaves. Among the isolated bacteriaꎬ 16S rDNA sequence alignment and
phylo ̄genetic tree analysis revealed that the presence of 906 bacterial strains were classified into 26 genera and 40
species. (2) While the smaller leaves were colonized by the largest number of endophytic bacterial species with a
relatively uniform community structureꎬ the opposite was true for bacteria isolated from the red ̄ and yellow ̄pigmented
leaves. (3) Comparison of the bacterial community data for abnormally colored leaves and those with the normally red ̄
color revealed that not only were there significant differences with respect to the dominant genera and speciesꎬ but also
an enrichment of numerous bacterial species in the genera Methylobacterium and Pseudomonas in the five types of
abnormally colored leaves. Particularlyꎬ we detected significantly larger numbers of Pseudomonas oryzihabitans. (4) We
established that abnormally colored leaves (smallerꎬ red spottedꎬ and the red and yellow types) were characterized by an
enrichment of bacteria with phosphorus solubilizationꎬ nitrogen fixationꎬ IAA productionꎬ and salt tolerance functionsꎬ
among whichꎬ four strains were found to have all four of these functions. Accordinglyꎬ we speculate that the abnormal
leaf coloration of L. chinense var. rubrum is closely associated with the activities of these enriched functional bacteria. Our
findings in this study indicate that the abnormal leaf coloration of L. chinense var. rubrum is closely associated with the
enrichment of specific endophytic bacterial communitiesꎬ which can thus provide clues for elucidating the mechanisms
underlying the development of abnormal leaf color in this plant. Moreoverꎬ this may have important application value for
the efficient cultivation of high ̄quality L. chinense var. rubrum.
Key words: Loropetalum chinense var. rubrumꎬ abnormal leaf colorꎬ endophytic bacteriaꎬ bacterial diversityꎬ
community structure
红 花 檵 木 ( Loropetalum chinense var. rubrum) 内生细菌的多样性研究ꎬ也未有关于频发的异常
又称 红 檵 木、 红 桎 木 等ꎬ 是 金 缕 梅 科 叶色 现 象 与 叶 片 内 生 细 菌 及 其 群 落 的 相 关 性
(Hamamelidaceae)檵木属( Loropetalum) 木本植物ꎬ 探索ꎮ
湖南省著名的乡土彩叶植物ꎬ具有良好的观赏、生 植物内生菌是寄存于植物体内不会对植物产
态环境保护及药用价值( 郭佩瑶等ꎬ2022)ꎮ 近年 生明显病害或暂时对植物没有伤害作用的微生
来ꎬ红花檵木异常叶色叶片现象逐渐受到国内学 物ꎮ 在适宜的植物内环境中ꎬ内生菌的多样性丰
者关注ꎬ张艺帆等(2022) 发现红花檵木季节性异 富、优势 度 低、 细 菌 种 类 分 布 均 匀 ( Stone et al.ꎬ
常叶色叶片现象对植物本身并无伤害ꎬ只是在夏 2000ꎻ江 曙 等ꎬ 2008ꎻ 顾 美 英 等ꎬ 2021ꎻ 孟 磊 等ꎬ
秋季节叶片出现较为明显的异常叶色叶片现象ꎬ 2023)ꎮ 此外ꎬ内生菌与宿主植物之间存在的共生
而在冬春季节异常叶色叶片现象逐渐减少甚至消 关系不仅能提高植物的抗逆能力、防治病害ꎬ还具
失ꎮ 王燕和朱发仁(2007)认为红花檵木异常叶色 有促生、固氮、生物修复等作用(Wani et al.ꎬ 2015ꎻ
叶片现象是由植物病毒而导致ꎬ但其并未明确该 Daniel et al.ꎬ 2016ꎻ Bak & Gajꎬ 2016)ꎮ 相关研究
现象 发 生 的 具 体 原 因ꎮ 王 慧 ( 2023) 对 许 璐 等 发现ꎬ细菌侵入、细菌类群变化、细菌性病害等会
(2021)定义的小叶、红黄相间、黄绿相间、完全黄 导致植物局部或全株出现色泽异常现象ꎬ在柑橘、
化、红斑 5 种典型红花檵木异常叶片类型的诱因 水稻植物中也发现了引起植株叶色变化的细菌微
研究发现ꎬ红花檵木异常叶色现象并非由细菌性 生物(谢志奎等ꎬ2021ꎻ陈苗苗和陈列忠ꎬ2022)ꎮ
病害、真菌性病害或缺素症而引起ꎮ 但是目前ꎬ国 因此ꎬ初步推断红花檵木异常叶色变化现象或与
内外对红花檵木的研究集中在栽培育种、生理特 内生细菌生存环境或菌群变化有关ꎬ红花檵木叶
性、化学成分等方面ꎬ对红花檵木异常叶色叶片现 片可能是在其独特的生理响应下导致叶片内环境
象的研究仅关注在其表型、光合特性和病害等方 发生变化ꎬ进而引起叶片内生细菌多样性、优势
面(许璐等ꎬ2021ꎻ张艺帆等ꎬ2022)ꎬ尚无红花檵木 度、种类分布等的改变ꎬ而细菌群落的改变又反作